1. Field of the Invention
This invention relates generally to perpendicular magnetic recording systems, and more particularly to a system with fast switching of the magnetization direction of the perpendicular write head.
2. Description of the Related Art
Perpendicular magnetic recording, wherein the recorded bits are stored in a perpendicular or out-of-plane orientation in the recording layer, allows for ultra-high recording densities in magnetic recording hard disk drives. The write head must be able to write data not only at high bit-density but also at high data-rates. The write speed is particularly important in enterprise disk drives. However, the switching time for the write pole of the write head to switch from one magnetization direction to the other is a limiting factor as the data rate is increased. At high data-rates, the available magnetic flux from the write head, as seen by the recording layer on the disk, is limited by the low-frequency flux output of the write head. The reason for such loss of write flux includes a slow intrinsic time-constant of the magnetization reversal in the main pole of the write head.
It is known that additional overshoot of the write current from the disk drive's write driver circuitry can aid in the magnetization reversal speed. Write enhancement circuitry that provides additional overshoot beyond that provided by the write driver circuitry aids in overcoming signal transmission losses and reduces the required overshoot from the write driver. A faster reversal time with a lower write driver overshoot requirement significantly reduces the power of the overall front-end write system, i.e., the write driver, the interconnect between the write driver and the write head, and the write head. What is needed is write enhancement circuitry separate from the write driver that provides additional overshoot of the write current and that can be fabricated on the head carrier at the same time and using the same processes that are used to fabricate the read and write heads.